Debug.Trace.Text

Text variant of the tracing functions in Debug.Trace.

Eventlog tracing

Eventlog tracing is a performance profiling system. These functions emit extra events into the eventlog. In combination with eventlog profiling tools these functions can be used for monitoring execution and investigating performance problems.

traceEvent :: Text -> a -> a

Text variant of traceEvent.

\(O(n)\) This function marshals the Text into a ByteString and convert it into a null-terminated CString.

Note that this function doesn't evaluate the Text if user tracing in eventlog is disabled.

The input should be shorter than \(2^{16}\) bytes. Otherwise the RTS generates a broken eventlog.

traceEventIO :: Text -> IO ()

Text variant of traceEventIO.

\(O(n)\) This function marshals the Text into a ByteString and convert it into a null-terminated CString.

Note that this function doesn't evaluate the Text if user tracing in eventlog is disabled.

The input should be shorter than \(2^{16}\) bytes. Otherwise the RTS generates a broken eventlog.

Execution phase markers

When looking at a profile for the execution of a program we often want to be able to mark certain points or phases in the execution and see that visually in the profile.

For example, a program might have several distinct phases with different performance or resource behaviour in each phase. To properly interpret the profile graph we really want to see when each phase starts and ends.

Markers let us do this: we can annotate the program to emit a marker at an appropriate point during execution and then see that in a profile.

traceMarker :: Text -> a -> a

Text variant of traceMarker.

\(O(n)\) This function marshals the Text into a ByteString and convert it into a null-terminated CString.

Note that this function doesn't evaluate the Text if user tracing in eventlog is disabled.

The input should be shorter than \(2^{16}\) bytes. Otherwise the RTS generates a broken eventlog.

traceMarkerIO :: Text -> IO ()

Text variant of traceMarkerIO.

\(O(n)\) This function marshals the Text into a ByteString and convert it into a null-terminated CString.

Note that this function doesn't evaluate the Text if user tracing in eventlog is disabled.

The input should be shorter than \(2^{16}\) bytes. Otherwise the RTS generates a broken eventlog.